Buy an 8 quart container and add this as the lid.

https://www.amazon.com/Cellar-Made-Anova-Rubbermaid-Container/dp/B083BWSMG2/ref=mp_s_a_1_3?crid=38VEBSIZ50E5J&keywords=8+quart+sous+vide+container&qid=1674970339&sprefix=8quart+sous%2Caps%2C210&sr=8-3

No insulation needed, in my opinion.